The present disclosure relates to methods and compositions for use in subterranean and oilfield operations. In particular, the present disclosure relates to methods and compositions for treating inorganic sulfide scales.
Treatment fluids can be used in a variety of subterranean treatment operations. Such treatment operations can include, without limitation, drilling operations, stimulation operations, production operations, sand control treatments, and the like. As used herein, the terms “treat,” “treatment,” “treating,” and grammatical equivalents thereof refer to any subterranean operation that uses a fluid in conjunction with achieving a desired function and/or for a desired purpose. Use of these terms does not imply any particular action by the treatment fluid. Illustrative treatment operations can include, for example, fracturing operations, gravel packing operations, acidizing operations, scale dissolution and removal, consolidation operations, and the like.
When the well or subterranean formation being treated is sour (i.e., the fluids in the well or subterranean formation contain a significant quantity of sulfide compounds, and particularly hydrogen sulfide), problems may be encountered as a result of the precipitation of inorganic sulfides in the presence of metal ions (mainly iron, zinc, and lead) that are also dissolved in the well or subterranean formation. In particular, the dissolved sulfide ions and the dissolved metal ions may form an inorganic sulfide precipitate, and this the precipitate may form inorganic sulfide scales when deposits as a solid matrix layer on a surface of the well or subterranean formation. These inorganic sulfide scales can plug the treated formation and cause damage to the well. Moreover, inorganic sulfide scales can be difficult to inhibit and remove.
Several approaches have been used to mitigate the problems caused by these sulfide scales. One traditional way to remove sulfide scales is through the use of an acid treatment. However, a re-treatment is often required due to the new sulfide scale deposit formation. Alternatively, previously efforts have focused on inhibiting these inorganic scales from being created through the use of different scale inhibitors that prevent the inorganic sulfide precipitate from forming. However, this approach often requires high dosage of scale inhibitors with limited efficiency.
While embodiments of this disclosure have been depicted, such embodiments do not imply a limitation on the disclosure, and no such limitation should be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.